The 1,5-benzothiazepine ring represents a heterocyclic moiety well known from the art. 1,5-Benzothiazepine-4-one derivatives bearing a double bond between the 2 and 3 positions and substituted at the positon 3 by alkyl, alkoxy, halo or trifluoromethyl are described in U.S. Pat. Nos. 3,895,006 and 3,983,106. These compounds are said to possess an antidepressant activity. Other 1,5-benzothiazepine-4-one derivatives are known from U.S. Pat. No. 3,646,008, in which 3-alkoxycarbonyloxy-1,5-benzothiazepine-4-one compounds are claimed, and U.S. Pat. No. 3,562,257 in which the substituents at the position 3 of the 1,5-benzothiazepine nucleus is a lower aliphatic acyloxy group from 1 to 4 carbon atoms. 3-Acyloxy-1,5-benzothiazepine-4-ones, in which the 3-acyloxy group is other than lower aliphatic acyl, as well as 3-phenyl or 3-(substituted phenyl)-carbamoyloxy-1,5-benzothiazepine-4-ones are, however, completely new.